FAQ — Redis

How does Redis Sentinel work on Hikube?

Redis on Hikube is deployed via the Spotahome Redis Operator, which sets up a Redis Sentinel architecture for high availability:

• Redis Sentinel monitors Redis instances and performs automatic failover when the primary fails.
• A quorum is required to decide on failover: you need at least 3 replicas to guarantee a working quorum (majority of 2 out of 3).
• Clients should connect via the Sentinel service to benefit from automatic failover.

redis.yaml

spec:
  replicas: 3    # Minimum recommended for Sentinel quorum

tip

In production, always use at least 3 replicas to ensure proper Sentinel quorum operation.

What is the difference between resourcesPreset and resources?

The resourcesPreset field lets you choose a predetermined resource profile for each Redis replica. If the resources field (explicit CPU/memory) is defined, resourcesPreset is completely ignored.

Preset	CPU	Memory
nano	250m	128Mi
micro	500m	256Mi
small	1	512Mi
medium	1	1Gi
large	2	2Gi
xlarge	4	4Gi
2xlarge	8	8Gi

redis.yaml

spec:
  # Using a preset
  resourcesPreset: small

  # OR explicit configuration (the preset is then ignored)
  resources:
    cpu: 1000m
    memory: 1Gi

Does Redis persist data?

Yes. Redis on Hikube uses RDB/AOF persistence combined with persistent volumes (PVC). Data is written to disk and survives pod restarts.

The storageClass choice affects durability:

• local: data persisted on the physical node. Fast but vulnerable to node failure. Recommended if replicas > 1 (Redis Sentinel replication already ensures HA).
• replicated: data replicated across multiple nodes. Slower but resilient to failures. Recommended if replicas = 1 (replicated storage compensates for the lack of application replication).

redis.yaml

spec:
  size: 2Gi
  storageClass: local    # If replicas > 1 (Sentinel ensures HA)

What is the authEnabled parameter for?

When authEnabled is set to true (default value), a password is automatically generated and stored in a Kubernetes Secret. This password is required for any connection to Redis.

redis.yaml

spec:
  authEnabled: true    # Default value

warning

Always enable authEnabled: true in production. Disabling authentication exposes your data to any pod that can access the Redis service.

How to scale Redis?

To increase the number of Redis replicas, modify the replicas field in your manifest and apply the change:

redis.yaml

spec:
  replicas: 5    # Increase the number of replicas

kubectl apply -f redis.yaml

Redis Sentinel automatically reconfigures the cluster to integrate the new replicas. No manual intervention is required.

How to connect to Redis from a pod?

1. Get the password from the Secret (if authEnabled: true):

   kubectl get tenantsecret redis-<name>-auth -o jsonpath='{.data.password}' | base64 -d

2. Connect via the Sentinel service (recommended for automatic failover):

   # Sentinel service
   redis-cli -h rfs-redis-<name> -p 26379 SENTINEL get-master-addr-by-name mymaster

3. Or connect directly to the Redis service:

   # Direct service
   redis-cli -h rfr-redis-<name> -p 6379 -a <password>

tip

Prefer connecting via the Sentinel service (rfs-redis-<name>) so your applications automatically follow the primary during failover.